Press brake with automatically variable length bending tool

Abstract

A press brake for metal sheets is described, comprising a tool for bending the metal sheet; the tool comprising a die and pressure means opposite to said die and adapted to press the metal sheet against the die to determine the bending of the metal sheet. The pressure means comprise a plurality of first segments aligned along the bending direction of the metal sheet and adapted to press said metal sheet against the die. The press brake comprises control means adapted to change the longitudinal dimension of the pressure means; the control means are adapted to individually drive each first segment for its longitudinal sliding along the bending direction of the metal sheet, so that the longitudinal dimension of the pressure means corresponds to the longitudinal dimension of the fold to be carried out on the metal sheet.

1 . Press brake for metal sheets comprising a tool for bending the metal sheet, said tool comprising a die and pressure means opposite to said die and adapted to pressing the metal sheet against the die to determine the bending of the metal sheet, said pressure means comprising a plurality of first segments aligned along the bending direction of the metal sheet and adapted to press said metal sheet against said die and said press brake comprises control means adapted to change the longitudinal dimension of said pressure means, said control means being adapted to individually drive each first segment for its longitudinal sliding along the bending direction of the metal sheet so that the longitudinal dimension of the pressure means corresponds to the longitudinal dimension of the fold to effectuate on the metal sheet, said pressure means comprising a plurality of second segments, said control means being adapted to individually drive each second segment for inserting it between said first segments so that the second segment is aligned to the first segments along the bending direction of the metal sheet and so that the longitudinal dimension of the pressure means comprising at least one first segment and at least one second segment corresponds to the longitudinal dimension of the fold to effectuate on the metal sheet, characterized in that said control means comprises first means adapted to determine the insertion of at least one second segment between two first segments by means of a movement transversal to the bending direction of the metal sheet, said first means comprise movement means configured to carry out a combination of a rotation movement and a translation movement of said at least one second segment for inserting said at least one second segment between two first segments. 
     
     
         2 . Press brake according to  claim 1 , wherein all the first segments have the same longitudinal dimension. 
     
     
         3 . Press brake according to  claim 1 , wherein each second segment has a longitudinal dimension lower or higher than each first segment. 
     
     
         4 . Press brake according to  claim 1 , wherein said first means comprise a plate longitudinally sliding on a fixed part of the press brake and movement means for each second segment, said movement means comprising a rotation motorized joint and a motorized translation joint connected with the second segment. 
     
     
         5 . Press brake according to  claim 4 , wherein said fixed part of the press brake is located above said first segments and in that said pressure means comprises a hollow guide for the arrangement of said first segments and in that said motorized translation joint comprises a first arm and a second arm sliding connected with the first arm and carrying at an end said second segment, said movement means determining said insertion of at least one second segment between two first segments by sliding directed downward of the second arm on the first arm, by rotation of the first arm by means of a rotation of the rotation joint and sliding directed upward of the second arm on the first arm for inserting said second segment inside the hollow guide of the pressure means. 
     
     
         6 . Press brake according to  claim 1 , wherein said control means comprise two longitudinal bars arranged one successive the other along the bending direction of the metal sheet and second means adapted to longitudinally move said two longitudinal bars, each first segment comprising a longitudinal through hole for engagement with one of said two longitudinal bars and an actuator, said actuator being adapted to block the first segment at one of the two longitudinal bars for the longitudinal sliding of the same first segment. 
     
     
         7 . Press brake according to  claim 6 , wherein said two longitudinal bars are spaced by a empty space for the insertion of at least one second segment between said at least two first segments belong to two bars, said control means being adapted to control two bars and the relative actuators for the longitudinal movement of said at least two first segments toward the at least one inserted second segment until said at least two first segments are adjacent to the at least one inserted second segment so that interruptions of the pressure means along the bending line of the metal sheet are not present. 
     
     
         8 . Press brake according to  claim 1 , wherein each one of said first segments comprises an end adapted to engage with the edges of the metal sheet which are bent in U shape. 
     
     
         9 . Press brake according to  claim 6 , wherein each one of said first segments comprises an end adapted to engage with the edges of the metal sheet which are bent in U shape, and said control means, in the case wherein the metal sheet has edges bent in U shape, are adapted to control the first means so as to go the at least one second segment away from said space between two first segments, said control means being adapted to successively control said two longitudinal bars and the actuators relative to the at least two first segments for longitudinally moving said at least two first segments toward the space which is left empty by the at least one second segment so as to allow the removal of the metal sheet with edges bent in U shape. 
     
     
         10 . Press brake according to  claim 1 , wherein said control means are adapted to place said first segments and said second segments adjacent to each other along the bending direction of the metal sheet.